This proposal requests support for the purchase of a Betascope 603 Blot Analyzer-Image Analysis System. The instrument provides real time data processing and image construction of radioactive samples deposited on gels or blots routinely utilized in molecular biological research. As a replacement for autoradiography, the Betascope provides finely detailed images 20-25 times faster than conventional x-ray film. For example, blots or gels normally requiring overnight exposure are typically imaged with the Betascope within 30-45 min. Most importantly, the instrument has the ability to accurately quantitate levels of 32P over a linear response range of 5 orders of magnitude per 10 square mm thus permitting precise quantitation of individual bands, dots etc. By comparison, densitometer scans of autoradiographs have linear ranges of roughly 2 orders of magnitude. In addition, the system provides for superior data management capabilities. All of the numerical data from an analysis are stored as digitized information suitable for spreadsheet and graph analysis utilizing computer software also provided with the instrument. The Betascope will be a multiuser instrument utilized primarily by a group of 10 investigators within the Department of Cellular and Structural Biology. This group of major users are all supported by NIH grants; their total support for 1989 is more than $1.4 million in direct costs. In addition, the instrument will be available on a priority basis to other investigators within the institution who have NIH grant support or who are collecting preliminary data in order to apply for grant support.